With the increasing popularity of portable apparatuses such as a mobile phone, a Personal Digital Assistant (hereafter to be referred as PDA), a notebook computer and so on, the input modes are becoming more and more humanized. Touch screen technology has become one of the simplest and the most convenient man-machine interactive input technologies. Currently, the mainstream touch screen technology has the following several types: a resistance type, a capacitance type, an infrared type and an inductance type.
Among them, a handwritten input apparatus with an inductance type touch screen consists of a touch pen, an antenna array board and a corresponding identification processing circuit. The touch pen is also called as an electromagnetic pen, wherein an LC oscillator is installed and used for transmitting electromagnetic signals in fixed frequency. A display panel and the antenna array board are overlapped together. The antenna array board consists of a plurality of the antennas covering the whole display panel and has at least two layers, which are used for detecting coordinate positions in the horizontal and vertical directions respectively. When the electromagnetic pen is close to or touches the display panel, the electromagnetic signal in the electromagnetic pen facilitates some of the antennas of the antenna array board to have a resonance and then generate oscillatory waves with the same frequency. Through the analysis for amplitudes and frequency of the oscillatory waves, the coordinate position of the electromagnetic pen relative to the display panel can be calculated. For example, in the U.S. patent application Ser. No. 06/937,231, it proposes a passive input pen with LC resonance. That is, the handwritten input can be realized based on electromagnetic induction principle.
Currently, with the development of handwritten input technology, people make higher requests for controllability, operational convenience and other aspects of the handwritten input technology. However, due to the richness of input information, this prior electromagnetic pen can not match up with the operations of humanized input software and the interface thereof, resulting in limiting the development of the industry for touch type input products with richer input means.